Carotid-ventricular coupling during exercise

Objectives-To evaluate carotid elasticity and left ventricular elastance during a graded bicycle semisupine exercise test in patients with known or suspected coronary artery disease and compare them with a control group of healthy young volunteers. Methods-Thirty-six elderly patients and 18 young healthy volunteers were recruited. The right carotid diameter was estimated by an automatic system applied to B-mode sonographic sequences, central mean blood and pulse pressures by radial artery tonometry, and cardiac volumes by 2-dimensional transthoracic echocardiography; from these direct measurements, the carotid cross-sectional distensibility coefficient and left ventricular elastance index were obtained. Analyses were performed at rest, at peak stress, and during the recovery phase. Results-The elderly patients included 20 men (mean age ± SD, 61 ± 8 years); the volunteers included 9 men (mean age, 34 ± 3 years). The mean blood pressure (at rest: patients, 97 ± 7 mm Hg; controls, 93 ± 9 mm Hg; not significant) increased similarly in both groups during exercise and decreased during the recovery phase. The diameter was higher in patients than controls (7.5 ± 1.1 versus 6.2 ± 0.5 mm) and increased significantly with exercise only in the latter group (at peak: 6.5 ± 0.6 mm; P < .05). The distensibility coefficient and elastance index were lower in patients than controls during the test phases [at rest: 24.5 ± 10.2 versus 60.8 ± 21.3 × 10-3/kPa and 3.6 ± 1.4 versus 1.6 ± 0.8 mm Hg/(mL/m2)] and mostly changed in the controls, showing a decreased distensibility coefficient (peak: 40.6 ± 15.1 × 10-3/kPa) and an increased elastance index [peak: 5.9 ± 2.8 mm Hg/(mL/m2)]. Conclusions-In older patients with multiple cardiovascular risk factors or established coronary artery disease, an abnormal carotid-ventricular adaptation to exercise was observed when compared to young healthy individuals.